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//File Convert_SphereToBSplineSurface.cxx
//JCV 16/10/91
#include <Convert_SphereToBSplineSurface.ixx>
#include <gp.hxx>
#include <gp_Trsf.hxx>
static const Standard_Integer TheUDegree = 2;
static const Standard_Integer TheVDegree = 2;
static const Standard_Integer MaxNbUKnots = 4;
static const Standard_Integer MaxNbVKnots = 3;
static const Standard_Integer MaxNbUPoles = 7;
static const Standard_Integer MaxNbVPoles = 5;
static void ComputePoles ( const Standard_Real R,
const Standard_Real U1,
const Standard_Real U2,
const Standard_Real V1,
const Standard_Real V2,
TColgp_Array2OfPnt& Poles)
{
Standard_Real deltaU = U2 - U1;
Standard_Real deltaV = V2 - V1;
Standard_Integer i, j;
// Nombre de spans : ouverture maximale = 150 degres ( = PI / 1.2 rds)
Standard_Integer
nbUSpans = (Standard_Integer)IntegerPart( 1.2 * deltaU / PI) + 1;
Standard_Integer
nbVSpans = (Standard_Integer)IntegerPart( 1.2 * deltaV / PI) + 1;
Standard_Real AlfaU = deltaU / ( nbUSpans * 2);
Standard_Real AlfaV = deltaV / ( nbVSpans * 2);
Standard_Integer nbVP = 2 * nbVSpans + 1;
Standard_Real x[MaxNbVPoles];
Standard_Real z[MaxNbVPoles];
x[0] = R * Cos( V1);
z[0] = R * Sin( V1);
Standard_Real VStart = V1;
for ( i = 1; i <= nbVSpans; i++) {
x[2*i-1] = R * Cos( VStart + AlfaV) / Cos( AlfaV);
z[2*i-1] = R * Sin( VStart + AlfaV) / Cos( AlfaV);
x[2*i] = R * Cos( VStart + 2 * AlfaV);
z[2*i] = R * Sin( VStart + 2 * AlfaV);
VStart += 2*AlfaV;
}
Standard_Real UStart = U1;
for ( j = 0; j <= nbVP-1; j++) {
Poles( 1, j+1) = gp_Pnt(x[j]*Cos(UStart),x[j]*Sin(UStart),z[j]);
}
for ( i = 1; i <= nbUSpans; i++) {
for ( j = 0; j<= nbVP-1; j++) {
Poles( 2*i, j+1) = gp_Pnt( x[j] * Cos(UStart+AlfaU) / Cos(AlfaU),
x[j] * Sin(UStart+AlfaU) / Cos(AlfaU),
z[j] );
Poles(2*i+1,j+1) = gp_Pnt( x[j] * Cos(UStart+2*AlfaU),
x[j] * Sin(UStart+2*AlfaU),
z[j] );
}
UStart += 2*AlfaU;
}
}
//=======================================================================
//function : Convert_SphereToBSplineSurface
//purpose :
//=======================================================================
Convert_SphereToBSplineSurface::Convert_SphereToBSplineSurface
(const gp_Sphere& Sph,
const Standard_Real U1 ,
const Standard_Real U2 ,
const Standard_Real V1 ,
const Standard_Real V2 )
: Convert_ElementarySurfaceToBSplineSurface (MaxNbUPoles, MaxNbVPoles,
MaxNbUKnots, MaxNbVKnots,
TheUDegree , TheVDegree)
{
Standard_Real deltaU = U2 - U1;
Standard_Real deltaV = V2 - V1;
Standard_DomainError_Raise_if( (deltaU>2*PI) || (deltaU<0.) ||
(V1 < -PI/2.0) || (V2 > PI/2),
"Convert_SphereToBSplineSurface");
isuperiodic = Standard_False;
isvperiodic = Standard_False;
Standard_Integer i,j;
// construction de la sphere dans le repere de reference xOy.
// Nombre de spans : ouverture maximale = 150 degres ( = PI / 1.2 rds)
Standard_Integer
nbUSpans = (Standard_Integer)IntegerPart( 1.2 * deltaU / PI) + 1;
Standard_Integer
nbVSpans = (Standard_Integer)IntegerPart( 1.2 * deltaV / PI) + 1;
Standard_Real AlfaU = deltaU / ( nbUSpans * 2);
Standard_Real AlfaV = deltaV / ( nbVSpans * 2);
nbUPoles = 2 * nbUSpans + 1;
nbVPoles = 2 * nbVSpans + 1;
nbUKnots = nbUSpans + 1;
nbVKnots = nbVSpans + 1;
Standard_Real R = Sph.Radius();
ComputePoles( R, U1, U2, V1, V2, poles);
for ( i = 1; i<= nbUKnots; i++) {
uknots(i) = U1 + (i-1) * 2 * AlfaU;
umults(i) = 2;
}
umults(1)++; umults(nbUKnots)++;
for ( i = 1; i<= nbVKnots; i++) {
vknots(i) = V1 + (i-1) * 2 * AlfaV;
vmults(i) = 2;
}
vmults(1)++; vmults(nbVKnots)++;
// On replace la bspline dans le repere de la sphere.
// et on calcule les poids de la bspline.
Standard_Real W1, W2;
gp_Trsf Trsf;
Trsf.SetTransformation( Sph.Position(), gp::XOY());
for ( i = 1; i <= nbUPoles; i++) {
if ( i % 2 == 0) W1 = Cos(AlfaU);
else W1 = 1.;
for ( j = 1; j <= nbVPoles; j++) {
if ( j % 2 == 0) W2 = Cos(AlfaV);
else W2 = 1.;
weights( i, j) = W1 * W2;
poles( i, j).Transform( Trsf);
}
}
}
//=======================================================================
//function : Convert_SphereToBSplineSurface
//purpose :
//=======================================================================
Convert_SphereToBSplineSurface::Convert_SphereToBSplineSurface
(const gp_Sphere& Sph ,
const Standard_Real Param1,
const Standard_Real Param2,
const Standard_Boolean UTrim )
: Convert_ElementarySurfaceToBSplineSurface (MaxNbUPoles, MaxNbVPoles,
MaxNbUKnots, MaxNbVKnots,
TheUDegree , TheVDegree)
{
#ifndef No_Exception
Standard_Real delta = Param2 - Param1;
#endif
Standard_DomainError_Raise_if( (delta>2*PI) || (delta<0.),
"Convert_SphereToBSplineSurface");
Standard_Integer i, j;
Standard_Real deltaU, deltaV;
isuperiodic = !UTrim;
isvperiodic = Standard_False;
Standard_Real R = Sph.Radius();
Standard_Real W1, W2, CosU, CosV;
if ( isuperiodic) {
ComputePoles(R, 0., 2.*PI, Param1, Param2, poles);
nbUPoles = 6;
nbUKnots = 4;
deltaV = Param2 - Param1;
Standard_Integer
nbVSpans = (Standard_Integer)IntegerPart( 1.2 * deltaV / PI) + 1;
Standard_Real AlfaV = deltaV / ( nbVSpans * 2);
nbVPoles = 2 * nbVSpans + 1;
nbVKnots = nbVSpans + 1;
for ( i = 1; i <= nbUKnots; i++) {
uknots(i) = ( i-1) * 2. * PI /3.;
umults(i) = 2;
}
for ( i = 1; i <= nbVKnots; i++) {
vknots(i) = Param1 + (i-1) * 2 * AlfaV;
vmults(i) = 2;
}
vmults(1)++; vmults(nbVKnots)++;
CosU = 0.5; // = Cos(pi /3)
CosV = Cos(AlfaV);
}
else {
ComputePoles(R, Param1, Param2, -PI/2., PI/2., poles);
nbVPoles = 5;
nbVKnots = 3;
deltaU = Param2 - Param1;
Standard_Integer
nbUSpans = (Standard_Integer)IntegerPart( 1.2 * deltaU / PI) + 1;
Standard_Real AlfaU = deltaU / ( nbUSpans * 2);
nbUPoles = 2 * nbUSpans + 1;
nbUKnots = nbUSpans + 1;
vknots(1) = -PI/2.; vmults(1) = 3;
vknots(2) = 0.; vmults(2) = 2;
vknots(3) = PI/2.; vmults(3) = 3;
for ( i = 1; i <= nbUKnots; i++) {
uknots(i) = Param1 + (i-1) * 2 * AlfaU;
umults(i) = 2;
}
umults(1)++; umults(nbUKnots)++;
CosV = 0.5; // = Cos(pi /3)
CosU = Cos(AlfaU);
}
// On replace la bspline dans le repere de la sphere.
// et on calcule les poids de la bspline.
gp_Trsf Trsf;
Trsf.SetTransformation( Sph.Position(), gp::XOY());
for ( i = 1; i <= nbUPoles; i++) {
if ( i % 2 == 0) W1 = CosU;
else W1 = 1.;
for ( j = 1; j <= nbVPoles; j++) {
if ( j % 2 == 0) W2 = CosV;
else W2 = 1.;
weights( i, j) = W1 * W2;
poles( i, j).Transform( Trsf);
}
}
}
//=======================================================================
//function : Convert_SphereToBSplineSurface
//purpose :
//=======================================================================
Convert_SphereToBSplineSurface::Convert_SphereToBSplineSurface
(const gp_Sphere& Sph)
: Convert_ElementarySurfaceToBSplineSurface (MaxNbUPoles, MaxNbVPoles,
MaxNbUKnots, MaxNbVKnots,
TheUDegree , TheVDegree)
{
isuperiodic = Standard_True;
isvperiodic = Standard_False;
Standard_Real W1, W2;
Standard_Integer i, j;
nbUPoles = 6;
nbVPoles = 5;
nbUKnots = 4;
nbVKnots = 3;
// Construction de la sphere dans le repere reference xOy.
Standard_Real R = Sph.Radius();
ComputePoles( R, 0., 2.*PI, -PI/2., PI/2., poles);
uknots( 1) = 0.;
uknots( 2) = 2. * PI / 3.;
uknots( 3) = 4. * PI / 3.;
uknots( 4) = 2. * PI;
vknots( 1) = -PI/2.;
vknots( 2) = 0.;
vknots( 3) = PI/2.;
for ( i = 1; i <= 4; i++) {
umults( i) = 2;
}
vmults(1) = vmults(3) = 3;
vmults(2) = 2;
// On replace la bspline dans le repere de la sphere.
// et on calcule les poids de la bspline.
gp_Trsf Trsf;
Trsf.SetTransformation( Sph.Position(), gp::XOY());
for ( i = 1; i <= nbUPoles; i++) {
if ( i % 2 == 0) W1 = 0.5;
else W1 = 1.;
for ( j = 1; j <= nbVPoles; j++) {
if ( j % 2 == 0) W2 = Sqrt(2.) /2.;
else W2 = 1.;
weights( i, j) = W1 * W2;
poles( i, j).Transform( Trsf);
}
}
}
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